diff --git a/rtcllm/a2a.py b/rtcllm/a2a.py
index 4a15430..d44f0ec 100644
--- a/rtcllm/a2a.py
+++ b/rtcllm/a2a.py
@@ -18,7 +18,7 @@ class LLMAudioStreamTrack(AudioStreamTrack):
 			b = self.get_audio_bytes()
 			if b is None:
 				print('LLMAudioStreamTrack return None ...')
-				return b
+				return await super().recv()
 			frame = AudioFrame.from_ndarray(io.BytesIO(b), format='s16', layout='mono')
 			print('LLMAudioStreamTrack return frame ...')
 			return frame